Functional structural domain synthesis of anti-pancreatic carcinoma pectin-like polysaccharide RN1.

The great structural and functional diversity supports polysaccharides as favorable candidates for new drug development. Previously we reported that a drug candidate pectin-like natural polysaccharide, RN1 might target galectin-3 (Gal-3) to impede pancreatic cancer cell growth in vivo. However, the quality control of polysaccharide-based drug research faces great challenges due to the heterogeneity. A potential solution is to synthesize structurally identified subfragments of this polysaccharide as alternatives. In this work, we took RN1 as an example, and synthesized five subfragments derived from the putative repeating units of RN1. Among them, pentasaccharide 4 showed an approximative binding affinity to Gal-3 in vitro, as well as an antiproliferative activity against pancreatic BxPC-3 cells comparable to that of RN1. Further, we scaled up pentasaccharide 4 to gram-scale in an efficient synthetic route with a 6.9 % yield from D-galactose. Importantly, pentasaccharide 4 significantly suppressed the growth of pancreatic tumor in vivo. Based on the mechanism complementarity of galactin-3 inhibitor and docetaxel, the combination administration of pentasaccharide 4 and docetaxel afforded better result. The result suggested pentasaccharide 4 was one of the functional structural domains of polysaccharide RN1 and might be a leading compound for anti-pancreatic cancer new drug development.

Rapid and sensitive detection of nucleic acids using an RAA-CRISPR/Cas12b one-pot detection assay (Rcod).

Rapid, sensitive and specific methods are crucial for nucleic acid detection. CRISPR/Cas12b has recently been widely used in nucleic acid detection. However, due to its thermophagic property, DNA isothermal recombinase-aided amplification (RAA) and subsequent CRISPR/Cas12b detection require two separate reactions, which is cumbersome and inconvenient and may cause aerosol pollution. In this study, we propose an RAA-CRISPR/Cas12b one-pot detection assay (Rcod) for Bordetella pertussis detection without additional amplification product transfer steps. The time from sample processing to response time was less than 30 min using nucleic acid extraction-free method, and the sensitivity reached 0.2 copies/µL. In this system, Alicyclobacillus acidoterrestris Cas12b protein (AacCas12b) exhibited strong and specific trans-cleavage activity at a constant temperature of 37 °C, while the cis-cleavage activity was weak. This characteristic reduces the interference of AacCas12b with nucleic acids in the system. Compared with real-time PCR, our Rcod system detected B. pertussis in 221 clinical samples with a sensitivity and specificity of 97.96 % and 99.19 %, respectively, with nucleic acid extraction-free method. The rapid, sensitive and specific Rcod system provides ideas for the establishment of CRISPR-based one-step nucleic acid detection and may aid the development of reliable point-of-care nucleic acid tests. IMPORTANCE: Pertussis is an acute respiratory infection caused by B. pertussis that is highly contagious and potentially fatal, and early diagnosis is essential for the treatment of whooping cough. In this study, we found that AacCas12b has high and strongly specific trans-cleavage activity at lower temperatures. A RAA-CRISPR/Cas12b one-step detection platform (Rcod) without interference with amplification was developed. In addition, the combination of Rcod and nucleic acid extraction-free method can quickly and accurately detect the qualitative detection of B. pertussis, and the detection results are visualized, which makes the pathogen nucleic acid detection and analysis process simpler, and provides a new method for the rapid clinical diagnosis of B. pertussis.

Divergent and Stereoselective Synthesis of Ustusal A, (-)-Albrassitriol, and Elegansin D.

The first synthesis of ustusal A as well as expeditious access to (-)-albrassitriol is described as featuring a singlet oxygen [4 + 2] cycloaddition, achieving the desired stereoselectivity for the 1,4-cis-hydroxyl groups. Transformation of (+)-sclareolide to III followed by a key Horner-Wadsworth-Emmons (HWE) reaction and stereospecific allylic oxidation facilitated the first synthesis of elegansin D. The biological evaluation of these natural products together with seven elegansin D analogues was performed, among which several elegansin D analogues exhibited potential anticancer activity against liver cancer HepG2 cells (IC50 = 11.99-25.58 µM) with low cytotoxicity on normal liver HL7702 cells (IC50 > 100 µM).

An extraction-free method for rapid detection of CYP2C19 * 2/3/17 polymorphisms in one tube using melting curve analysis.

Drug-metabolizing enzymes play an important role in the metabolism of drugs in vivo. Their activity is an important factor affecting the rate of drug metabolism, which directly determines the intensity and persistence of drug action. Patients taking medication can be divided into different metabolic types through detection of CYP2C19 drug-metabolizing enzyme gene polymorphisms, which can then be used for medication guidance for clopidogrel. Here, we describe a detection method based on real-time polymerase chain reaction (PCR). This method uses multicolor melting curve analysis to accurately identify different mutation sites and genotypes of CYP2C19 * 2, CYP2C19 * 3, and CYP2C19 * 17. The detection limit of plasmid samples was 1 copies µL-1 ; that of genomic samples was 0.1 ng µL-1 . The system can detect nine types of CYP2C19 * 2/3/17 at three sites in one tube, quickly achieving detection within 1 h. Combined with the sample release agent, sample extraction was completed in 5 s, achieving rapid diagnosis without extraction for timely diagnosis and treatment. Furthermore, the system is not limited to blood samples and can also be applied to oropharyngeal and saliva samples, increasing sampling diversity and convenience. When using clinical blood samples (n = 93), the detection system we established was able to quickly and accurately identify different genotypes, and the accuracy and effectiveness of the detection were confirmed by Sanger sequencing. Due to its accuracy, rapidity, simple operation, and low cost, detection technology based on real-time polymerase amplification combined with melting curve analysis is expected to become a powerful tool for detecting and guiding clopidogrel use in countries with limited resources.

Melatonin Regulates Lipid Metabolism in Porcine Cumulus-Oocyte Complexes via the Melatonin Receptor 2.

Previous studies suggest that the inclusion of melatonin (MTn) in in vitro maturation protocols improves the developmental competence of oocytes by scavenging reactive oxygen species (ROS). However, the molecular mechanisms integrating melatonin receptor (MT)-mediated lipid metabolism and redox signaling during in vitro cumulus-oocyte complex (COC) development still remain unclear. Here, we aimed to elucidate the potential role of MTn receptors in lipid metabolic adjustments during in vitro porcine COC development. We observed that MTn-mediated Gsα-cAMP/PKA signaling facilitated lipolysis primarily through the MT2 receptor and subsequently increased fatty acid (FA) release by hydrolyzing intracellular triglycerides (TGs) in cumulus cells. Furthermore, CD36 was a critical FA transporter that transported available FAs from cumulus cells to oocytes and promoted de novo TG synthesis in the latter. In addition, MTn regulated lipogenesis and intracellular lipolysis to maintain lipid homeostasis and limit ROS production, thereby supporting oocyte cytoplasmic maturation and the subsequent embryo development. Taken together, these findings provide insight into the possible mechanism integrating MT2-mediated lipid homeostasis and redox signaling, which limits ROS production during in vitro COC development. Therefore, understanding the dynamics of the interactions between lipid homeostasis and redox signaling driven by MT2 is necessary in order to predict drug targets and the effects of therapeutics used to improve female reproductive health.

Multi-parameter optimization maximizes the performance of genetically engineered Geobacillus for degradation of high-concentration nitroalkanes in wastewater.

Nitroalkanes are important toxic pollutants for which there is no effective removal method at present. Although genetic engineering bacteria have been developed as a promising bioremediation strategy for years, their actual performance is far lower than expected. In this study, important factors affecting the application of engineered Geobacillus for nitroalkanes degradation were comprehensively optimized. The deep-reconstructed engineered strains significantly raised the expression and activity level of catalytic enzymes, but failed to fully enhance the degradation efficiency. However, further debugging of a variety of key parameters effectively improved the performance of the engineering strains. The increased cell membrane permeability, trace supplementation of vital nutritional factors, synergy of multifunctional enzyme engineered bacteria, switch of oxygen-supply mode, and moderate initial biomass all effectively boosted the degradation efficiency. Finally, a low-cost and highly effective bioreactor test for high-concentration nitroalkanes degradation proved the multi-parameter optimization mode helps to maximize the performance of genetically engineered bacteria.

Bacterial diversity and competitors for degradation of hazardous oil refining waste under selective pressures of temperature and oxygen.

Oil refining waste (ORW) contains complex, hazardous, and refractory components, causing more severe long-term environmental pollution than petroleum. Here, ORW was used to simulate the accelerated domestication of bacteria from oily sludges and polymer-flooding wastewater, and the effects of key factors, oxygen and temperature, on the ORW degradation were evaluated. Bacterial communities acclimated respectively in 30/60 °C, aerobic/anaerobic conditions showed differentiated degradation rates of ORW, ranging from 5% to 34%. High-throughput amplicon sequencing and ORW component analysis revealed significant correlation between bacterial diversity/biomass and degradation efficiency/substrate preference. Under mesophilic and oxygen-rich condition, the high biomass and abundant biodiversity with diverse genes and pathways for petroleum hydrocarbons degradation, effectively promoted the rapid and multi-component degradation of ORW. While under harsh conditions, a few dominant genera still contributed to ORW degradation, although the biodiversity was severely restricted. The typical dominant facultative anaerobes Bacillus (up to 99.8% abundance anaerobically) and Geobacillus (up to 99.9% abundance aerobically and anaerobically) showed oxygen-independent sustainable degradation ability and broad-spectrum of temperature adaptability, making them promising and competitive bioremediation candidates for future application. Our findings provide important strategies for practical bioremediation of varied environments polluted by hazardous ORW.

New iboga-type alkaloids from Ervatamia officinalis and their anti-inflammatory activity.

Four new iboga-type alkaloids, ervaoffines H-K (1-4), along with five known compounds were obtained from the aerial parts of Ervatamia officinalis. The absolute configurations of 1-4 were confirmed by X-ray diffraction and electronic circular dichroism (ECD) analyses. The isolates were tested for their anti-inflammatory activity. Compounds 1, 5, 6, and 9 showed potential inhibitory effect of NO production in LPS-stimulated BV2 and RAW264.7 cells.

Conformation-Controlled Hydrogen-Bond-Mediated Aglycone Delivery Method for α-Xylosylation.

α-Xylosylated glycans and xylosyl derivatives are biomedically important molecules which show numerous bioactivities against infection, cancer, inflammation, and so on. Lacking an efficient α-xylosylation method, the synthesis of α-xyloside-containing molecules was full of challenges. Herein, a robust method is presented for selective α-xylosylation via combination of a rare conformation-controlled strategy and the hydrogen-bond-mediated aglycone delivery method. Various native branched α-xyloside structures necessitate an orthogonally protected xyloside, and a three-pot preparation method of the xylosyl donor was developed for this novel α-xylosylation method, which was further applied in the first synthesis of the side chain N of xyloglucan. This work provides an efficient α-xylosylation method which would make various α-xyloside structures achievable. The conformation-controlled strategy also has important reference to the chemistry of five-carbon pyranose.

[Study on efficacy markers of Salviae Miltiorrhizae Radix et Rhizoma for promoting blood circulation and remving blood stasis based on systematic traditional Chinese medicine].

Traditional Chinese medicine for promoting blood circulation and removing blood stasis has been widely used in clinical practice. However, due to the diversity of the composition of traditional Chinese medicine and the complexity of its interaction with human body, it is difficult to apply traditional quality control ingredients to characterize its overall efficacy. Systematic traditional Chinese medicine is an effective method for studying the efficacy of traditional Chinese medicine, embodying the dialectical unity of holism and reductionism. Salviae Miltiorrhizae Radix et Rhizoma is a common traditional Chinese medicine for promoting blood circulation and removing blood stasis. In this study, we constructed a multi-dimensional network of "efficacy-pharmacological efficacy-targets-components" based on systematic traditional Chinese medicine, and discussed the discovery of the efficacy markers of Salviae Miltiorrhizae Radix et Rhizoma for promoting blood circulation and removing blood stasis. Firstly, based on the Chinese medicine efficacy-pharmacology database, the most relevant pharmacological actions(boundary) for promoting blood circulation and removing blood stasis(function) were obtained, and the target sets(structure) of the corresponding pharmacological action were obtained by the DrugBank database. Then, STRING database was used to construct protein-protein interaction network(relationship) of targets related to promoting blood circulation and removing stasis, and key targets(elements) in the network were selected by evaluating topological parameters of targets. Finally, the potential efficacy markers of Salviae Miltiorrhizae Radix et Rhizoma were predicted by molecular docking based on the key targets of promoting blood circulation and removing blood stasis. The results demonstrated that salvianolic acid B, salvianolic acid A, tanshinone Ⅱ_A and tanshinone Ⅰ were the potential markers of Salviae Miltiorrhizae Radix et Rhizoma on promoting blood circulation and removing blood stasis. Salvianolic acid B, salvianolic acid A, tanshinone Ⅱ_A had been reported to have anti-platelet aggregation, anti-thrombotic, cardiovascular protection and some other pharmacological functions. Based on systematic traditional Chinese medicine, we have preliminarily predicted the efficacy markers of Salviae Miltiorrhizae Radix et Rhizoma in promoting blood circulation and removing blood stasis in this study, providing a research method for the discovery of efficacy markers and a reference for the overall quality control of traditional Chinese medicine.

[Exploration of potential efficacy markers of Astragali Radix for invigorating Qi based on systematic traditional Chinese medicine].

Astragali Radix is the elixir for invigorating Qi, with the effects of invigorating Qi, promoting Yang and nourishing the body. With the deepening researches on the chemical constituents of Astragali Radix, it is used more extensively in clinical application. Based on systematic traditional Chinese medicine theory, in this paper, we characterized the effect of Astragali Radix on invigo-rating Qi from the molecular level, and explored the markers of Astragali Radix on invigorating Qi. Through TCMSP and ChEMBL databases, the active components-targets database of Astragali Radix was constructed to clarify the targets(elements) involved in Astragali Radix's Qi invigorating efficacy system. According to the relationship between the targets, the protein interaction network was constructed, and the network modules(structure) were divided according to the theoretic clustering algorithm molecular complex detection(MCODE), and the boundary of the Qi invigorating efficacy system was defined by the pharmacological function of Astragali Radix. The active components of Astragali Radix for invigorating Qi were characterized from the aspects of composition, target and efficacy. The results showed that eight key components of Astragali Radix, such as hederagenin, quercetin, calycosin, formononetin, jaranol, isorhamnetin, astragalosideⅢ, and 9,10-dimethoxypterocarpan-3-O-ß-D-glucoside, could act on eight functional modules composed of 17 key targets, and participate in G-protein coupled receptor protein signaling pathway, regulation of lipid metabolic process, positive regulation of nitrogen compound metabolic process, positive regulation of programmed cell death, fatty acid metabolic process and other biological processes to produce pharmacological effects such as regulating immune function, strengthening heart, protecting myocardial cells, improving material metabolism, and antioxidation effects, thus playing the role of invigorating Qi. Based on the systematic Chinese medicine theory, this study explored the effective markers of Astragali Radix at the level of molecular network, which provided new ideas for the interpretation of the effective substance basis of systematic traditional Chinese medicine and the quality control of traditional Chinese medicine. In the future, it can focus on the compatibility research of these components, and then carry out more in-depth studies on the efficacy of Astragali Radix in invigorating Qi, and strengthen the development of the corresponding pharmacological mechanism and related preparations.

[Discovery of intervention effect of Chinese herbal formulas on COVID-19 pulmonary fibrosis treated by VEGFR and FGFR inhibitors].

Since February 2020, a large number of patients infected with new coronavirus has been cured and discharged with the controlling of epidemic. Pulmonary fibrosis, which may be one of the sequela caused by COVID-19, not only brings dyspnea and deterioration of lung function, but also affects patients' life because of its high mortality and poor prognosis. Vascular endothelial growth factor receptor(VEGFR) and fibroblast growth factor receptor(FGFR) can inhibit the proliferation, activation and migration of fibroblasts by regulating the signal transduction pathway involved in the process of pulmonary fibrosis. Chinese herbal formulas pose a good therapeutic effect on pulmonary fibrosis. Present study explores the intervention effect on pulmonary fibrosis of traditional Chinese medicine(TCM) by screening the potential inhibitors of VEGFR and FGFR. The docking models of VEGFR and FGFR were established to obtain the potential active ingredients which were filtered by the docking score. According to 2 prescriptions in the Protocol for the diagnosis and treatment of coronavirus disease 2019(7th edition)and 9 prescriptions in Traditional Chinese medicine prescriptions for treating blight, 959 and 1 047 potential ingredients were obtained as the inhibitors of VEGFR and FGFR respectively with the screening thres-hold set as eighty percent of the docking score of the initial ligands. The potential herbs were then filtered by the components with a hit rate higher than 30%, such as Scutellariae Radix, Adenophorae Radix, Pinelliae Rhizoma, Coicis Semen, etc. To discuss the rule of TCM in the treatment of pulmonary fibrosis, the networks of TCM-channel tropism and TCM-efficacy of the potential herbs was constructed. The potential herbs for treating pulmonary fibrosis mostly belong to lung(degree=14) and spleen(degree value=8), and the efficacy is focused on reinforcing deficiency(degree=9). Qiyin Prescription and Buzhong Yiqi Decoction contain the largest number of the potential herbs. The main symptom of COVID-19 is damp-heat stagnating in the lung, which always causes impairment of body fluid and Qi. Clinical observation shows that patients in the recovery period are mostly at the status that the remaining virus toxicity is not exhausted while the vital Qi have not recovered. The results of this study are expected to provide references for clinical medication in preventing and treating pulmonary fibrosis caused by COVID-19.

A new isoflavone with anti-inflammatory effect from the seeds of Millettia pachycarpa.

A new isoflavone, milletenol A (1), along with four known flavonoids (2-5) were isolated from the seeds of Millettia pachycarpa. The structure of 1 was established by extensive spectroscopic methods while known compounds were identified by comparisons with literature data. Compound 1 and 2 showed significant anti-inflammatory activities against nitric oxide production in LPS-induced RAW264.7 macrophages. The state of CuSO4-stimulated inflammation was effectively alleviated by compound 1 in zebrafish. However, no significant cytotoxicity against human breast cancer cells was observed among all isolates.

[Determination of six active ingredients in different parts of Belamcanda chinensis and Iris tectorum and their anti-inflammatory activity].

In order to explore the anti-inflammatory activity and active ingredient basis from the leaves of the Belamcanda chinensis and Iris tectorum, we established an HPLC method for simultaneous determination of six anti-inflammatory active ingredient contents in the root of the B. chinensis and I. tectorum as well as their leaves with different dry methods, and the anti-inflammatory effects of the extract were studied by the mouse ear swelling experiment. The HPLC analysis was performed on an Agilent WondaSil© C18-WR(4.6 mm×250 mm，5 µm)，with isocratic elution of acetonitrile-0.1% ortho-phosphoric acid solution at a flow rate of 1. 0 mL·min⁻¹ and the detection was carried out at 265 nm. The chemical compositions of the B. chinensis and I. tectorum are similar but the contents of them are obviously different. Both rhizome and leaf extract of B. chinensis and I. tectorum had inhibitory effects on inflamed mice induced by dimethylbenzene and had anti-inflammatory effects by animal experiment, which could lay the material and active foundation for the development of the non-medicinal parts of the B. chinensis and I. tectorum.

Cloning, Expression, and Characterization of budC Gene Encoding meso-2,3-Butanediol Dehydrogenase from Bacillus licheniformis.

The budC gene encoding a meso-2,3-butanediol dehydrogenase (BlBDH) from Bacillus licheniformis was cloned and overexpressed in Escherichia coli BL21(DE3). Sequence analysis reveals that this BlBDH belongs to short-chain dehydrogenase/reductase (SDR) superfamily. In the presence of NADH, BlBDH catalyzes the reduction of diacetyl to (3S)-acetoin (97.3% ee), and further to (2S,3S)-2,3-butanediol (97.3% ee and 96.5% de). Similar to other meso-2,3-BDHs, it shows oxidative activity to racemic 2,3-butanediol whereas no activity toward racemic acetoin in the presence of NAD(+). For diacetyl reduction and 2,3-butanediol oxidation, the pH optimum of BlBDH is 5.0 and 10.0, respectively. Unusually, it shows relatively high activity over a wide pH range from 5.0 to 8.0 for racemic acetoin reduction. BlBDH shows lower K m and higher catalytic efficiency toward racemic acetoin (K m = 0.47 mM, k cat /K m = 432 s(-1)·mM(-1)) when compared with 2,3-butanediol (K m = 7.25 mM, k cat /K m = 81.5 s(-1)·mM(-1)), indicating its physiological role in favor of reducing racemic acetoin into 2,3-butanediol. The enzymatic characterization of BlBDH provides evidence for the directed engineering of B. licheniformis for producing enantiopure 2,3-butanediol.

[Effect of Xianxiong decoction on acute lung injury mice induced by lipopolysaccharide].

OBJECTIVE: To investigate the effect of Xianxiong decoction on the mice with acute lung injury induced by lipopolysaccharide. METHOD: Eighty female ICR mice were randomly divided into 8 groups: model group, Xianxiong decoction group, Daxianxiong decoction group, Xianxiong decoction group without Kansui Radix group, Xianxiong decoction group without Glycyrrhizae Radix et Rhizoma group, Glycyrrhizae Radix et Rhizoma and Kansui Radix group, normal group and control group. Animals of each group, except normal group, were undertaken intraperitoneal injection and intranasal inhalation of lipopolysaccharide (LPS) on day 1, 2, 3 to establish acute lung injury (ALI) model. 30 min after modeling, 0.2 mL corresponding drugs were administrated to each mice, dexam ethasone and normal saline were given to the mice of control group and normal group respectively. White blood cell in blood, neutrophil percentage of blood and bronchoalveolar lavage fluid (BALF) supernatant, the ratio of wet and dry lung tissue ( W/D), histopathological changes of lung tissue were estimated. Sixty ICR mice were randomly divided into normal, model, control, high, middle and low dose Xianxiong decoction groups and were modeled in the same way. ELISA was applied to detect the level of NF-kappaB, TNF-alpha and IL-6 in BALF, PCR for NF-kappaB and TNF-alpha mRNA in lung tissue, and Western blot for NF-kappaB and TNF-alpha. Half of 20 ICR mice were administrated with Xianxiong decoction of its maximum tolerant normal saline. RESULT: Compared with model group, the number of WBC in blood of Xianxiong decoction group mice decreased (P < 0.01), percentage of neutrophils in both blood and BALF decreased as well (P < 0.01, P < 0.05); it also significantly reduced the ratio of W/D (P < 0.01); and found the alveolar wall, the number of inflammatory cells infiltrating improved, compared with model group. Xianxiong decoction reduced the level of NF-kappaB, TNF-alpha and IL-6 in BALF (P < 0.01, P < 0.01, P < 0.05); its high and low dose groups only found TNF-alpha level declined. Five mice died 24 h after administration of Xianxiong decoction which indicated its toxicity when other influential factors were considered. CONCLUSION: Xianxiong decoction is effective on the ALI mice induced by LPS, but it is of toxicity at 3 g x mL(-1).

[Research on the origins and development of the verse "eighteen antagonism" in Chinese material medica].

The verse "eighteen antagonism" of Chinese materia medica is a kind of describing of drug nature concerning the incompatibility of drugs in compound prescription. Through organizing the medical books in different historical periods, it is found that the drugs in this verse basically coming from TAO Hong-jing's ben cao jing ji zhu (Variorum of Shennong's Classic of Materia Medica), while the style of verse mostly appeared during the Song-Jin-Yuan period was made. The formed verse was explained and supplemented further in the Ming Dynasty, the basis of which appeared in the Song-Jin-Yuan Dynasty, resulting in the increase of the number of antagonistic drugs and lengthy verse. The origin of the verse seen in Ru men shi qin (Confucians' Duties to Their Parents) and those in other books was not identical and was the most popular one after the Qing Dynasty, becoming the most popularly known even today.

[Influence of different duration of waterlogging on the growth and C and N metabolism of soybean at seedling and flowering stages].

A pot experiment with soybean cultivar Nannong 99-6 was conducted to study its growth and C and N metabolism at seedling and flowering stages under the stress of different duration of waterlogging. Waterlogging inhibited the soybean growth. The plant biomass, leaf area, leaf pigment content, and photosynthesis rate all decreased significantly, and the leaf malonyldialdehyde (MDA) content had a significant increase. The change ranges of the physiological indices increased with increasing waterlogging duration. After the release of the stress, the plants had some recovery. The recovery capability in treatment waterlogging for 10 d was stronger than that in the treatment waterlogging for 20 d. The leaf soluble C and N and key enzymes had different responses to waterlogging. Soluble sugar content and glutamine synthease and sucrose synthease activities all increased, but soluble protein content decreased. The influence of waterlogging on the plant biomass, leaf area, and MDA content was smaller at seedling stage than at flowering stage. It was suggested that the shorter the waterlogging duration was, the lesser damage the soybean plant suffered, and the stronger the recovery capability was. Soybean plant could recover itself after waterlogging for 10 d.

Antifeedant and insecticidal effects of mandelic acid on the brown planthopper Nilaparvata lugens Stål.

To study the effects of mandelic acid (MA) on the brown planthopper (BPH), Nilaparvata lugens, the survival rate and behaviour of BPH fed on an artificial diet with different dosages of MA was observed. The survival rate of BPH decreased with the increase of the MA concentration and feeding time. In contrast to the control, the survival rate of BPH 72 h after feeding decreased significantly. Electrical penetration graph (EPG) data indicated that MA absorbed by the rice plant from Kimura B solution significantly affected the feeding behaviour of BPH. At the concentrations of 0.1, 0.5, and 1.0 mg/ml, duration of the phloem ingestion of BPH decreased from 115.34 min (control) to 30.41, 7.63, and 0.36 min, respectively. Periods of xylem ingestion of MA-treated BPH were significantly shorter than those of the control (50.44 min). Moreover, BPH spent more time walking around or being at rest on MA-treated rice plants, as well as in stylet activities. The GST (glutathione S-transferase) activity of BPH increased with the increasing MA concentration, while the GPX (glutathione peroxidases) activity did not change significantly. The results indicate that MA has an antifeedant and insecticidal effect on BPH.